Surface spectroscopy and microscopy studies of functional molecular films at electrified interfaces

带电界面功能分子膜的表面光谱和显微镜研究

• 批准号: RGPIN-2022-02954
• 负责人: Lipkowski, Jacek
• 金额: $ 2.62万
• 依托单位: University of Guelph
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=747978
• 关键词: Surface; spectroscopy; microscopy; studies; functional

The general objective of this research program is to study the structure and reactivity of phospholipid bilayers deposited onto a metal electrode at the metal-solution interface. The functionality of these films will be determined by the presence of peptides and proteins. We will build asymmetric bilayer that mimics outer membrane (OM) of a gram-negative bacterium and will investigate interactions of the large antibacterial peptides with lipopolysaccharides (LPS) that constitute the outer leaflet of the outer bacteria membrane. Our goal is to learn how the peptides bound to the LPS and how they cause a poration of the membrane. We will investigate how the electric field affects the stability of the asymmetric bilayers in which top leaflet consisting of LPS and the bottom leaflet of phospholipids and incorporation of antibiotics into such membrane. We will use Langmuir-Schaeffer technique to assemble the asymmetric bilayer. We will employ electrochemical impedance spectroscopy (EIS) to provide information about the membrane barrier properties for the transport of ions (resistivity). The scanning probe microscopies such as scanning tunneling microscopy (STM) and atomic force microscopy (AFM) will be used to provide molecular level images of the monolayer of lipopolysaccharides (LPS) and the asymmetric bilayer. In situ photon polarization modulation Fourier transform infrared reflection absorption spectroscopy (PM-IRRAS), surface enhanced infrared (SEIRAS) and surface enhanced Raman spectroscopy (SERS) will be used to investigate conformation, orientation, interactions, and penetration of the peptides with and through the bilayer. The spectroscopic techniques are complementary; PM-IRRAS will provide information about steady state properties of the bilayer with and without the peptides. SEIRAS will be used to investigate kinetics of the structural changes induced by antibiotic peptides and their insertion or transport across the bilayer. SERS has unique potential for studies of polysaccharides. Its spectral range is extended down to very low wavenumbers and its signal is not affected by the spectral interferences caused by the presence of water. We will employ several platforms to obtain high quality SERS spectra of polysaccharides such as shell isolated gold nanoparticles, array of pure gold nanoparticles and array of gold nanocavities. In another theme we will apply spectroscopic tools to investigate the mechanism of bonding of CO2 reducing enzymes such as formate dehydrogenase, (FDH) without and with metal centers to conductive supports and their performance to convert CO2 to useful chemicals.  Our task will be to apply spectroscopic methods to provide information about the nature of the bond formed with conductive support, and structural changes of the enzyme accompanying changes of the redox state of its redox center.

该研究计划的一般目标是研究沉积在金属溶剂界面上金属电极上的磷脂双层的结构和反应性。这些薄膜的功能将取决于肽和蛋白质的存在。我们将建立不对称的双层，以模仿革兰氏阴性细菌的外膜（OM），并将研究大型抗菌辣椒与脂多糖（LPS）的相互作用，这些含糖（LPS）构成了外部细菌膜的外部传叶。我们的目标是了解Petides如何与LP绑定到LP，以及它们如何制定膜政策。我们将研究电场如何影响不对称双层的稳定性，其中由LPS和磷脂的底部小叶组成，以及抗生素的法规构成这种膜。我们将使用Langmuir-Schaeffer技术来组装不对称的双层。我们将采用电化学阻抗光谱（EIS）来提供有关离子运输（电阻率）的膜屏障特性的信息。扫描探针显微镜（例如扫描隧道显微镜（STM）和原子力显微镜（AFM））将用于提供脂多糖（LPS）单层（LPS）和非对称双层单层的分子水平图像。原位光子极化调制调节傅里叶感染分析光谱（PM-IRRAS），表面增强的感染（SEIRAS）和表面增强的拉曼光谱（SER）将用于研究Pepperides在倍层中和通过胆汁层和辣椒对辣椒的渗透。光谱技术已经完成； PM-IRRAS将提供有关双层带有和没有胡椒粉的双层稳态特性的信息。 SEIRAS将用于研究抗生素胡椒体及其在双层中的插入或运输引起的结构变化的动力学。 SER具有多糖研究的独特潜力。它的光谱范围延伸至非常低的波数，其信号不受由于水的存在引起的光谱相互作用的影响。我们将采用多个平台获得多糖的高质量SERS光谱，例如壳孤立的金纳米颗粒，纯金纳米颗粒和金纳米腔阵列。我们将采用光谱工具来研究二氧化碳键合酶（如形成脱氢酶，（FDH），没有金属中心）的键合的机制，以导电支持及其性能，以将二氧化碳转换为有用的化学物质。我们的任务是采用光谱方法来提供有关用导电支持形成的债券的性质的信息，以及其氧化还原中心氧化还原状态的酶的结构变化。